An objective of orthopedic surgery is to continue developing improved devices and methods that are less invasive to the patient. These efforts include minimizing the incision required to employ surgical instrumentation in the preparation of a bone cavity or socket to receive an implant in, e.g., an acetabular reaming procedure. A way to minimize the incision is to optimize the geometry that the reamer presents to the incision, characterized herein as its “static insertion profile area”. By simplifying the surgical steps required, the reamer design can further lessen total inter-operative time and hence decrease the risks generally associated with longer surgical times.
The present inventors have previously disclosed hollow domed acetabular reamers with hemispherical shapes, e.g., PCT/US99/05951 and U.S. Pat. Nos. 5,658,290 and 6,264,647, which are assembled to driving handles for controlled rotation about a cut axis during the reaming operation. Such prior art acetabular reamers present a circular static insertion profile area (with no straight sides) to the surgical incision, generating a circular dynamic profile area upon rotation of the reamer in the bone socket. A cotyloid reamer of one of the present inventors is shown in U.S. Pat. No. 6,106,536 having a much different i.e., lop-sided construction compared to the inventors' prior acetabular reamers. This cotyloid reamer presents a semi-circular static insertion profile area (i.e., one straight side) to the surgical incision, which is less than the circular dynamic profile area generated upon rotation of the reamer in the bone.
The entire contents of the present inventors' above-identified prior patent documents are entirely incorporated by reference herein and relied-upon.
Another approach taken by others, discussed below in conjunction with FIGS. 1-3 herein, has been to use an acetabular reamer of the above domed type, modified with straight sides, for purposes of a less invasive surgical procedure. Such reamers present a partially circular static insertion profile area to the surgical incision, which is defined by a pair of curved sides generated about a center coinciding with the rotational axis, separated by a pair of straight sides. Notwithstanding, it would still be beneficial to provide a reamer having a static insertion profile area that results in a less invasive reaming operation, in terms of minimized time through efficiency, as well as a minimized incision size.
Another objective of orthopedic surgery is to develop instrumentation that is more handily and efficiently used while accurately maintaining a precise cut of the bone socket, in order to minimize inter-operative time. The inventors' above-incorporated patent documents also discuss various alternative connections by which their reamers may be assembled to a handle, such assemblies including alignment structures on the reamer and handle allowing controlled rotation of the reamer in the bone socket. Such assembly mechanisms have included a reamer having a bar with centering hole and a bar with a centering boss. The inventors have also taught reamers having an alignment structure with a pair of bars mounted either in orthogonal intersecting relationship or extending chordally in parallel, for assembly with e.g., a bayonet catch or other structure(s) of the handle. The present inventors believe that the above-mentioned prior reamer-handle connections would, nevertheless, be further beneficial when used in reamers having a less invasive static insertion profile area.
Accordingly, it would still be desirable to reduce the static insertion profile area of the reamer to minimize the size of the surgical incision, while providing a precise cut of the desired bone cavity.
It would also be desirable to have connections between a reamer and handle that are designed to perform with a less invasive reamer geometry. It would further be desirable to have novel connections that function with different handles having a variety of bayonet or other assembly connections, regardless of reamer geometry.
It would further be desirable to provide a novel reamer tool-handle connection in either a conventional or a less invasive geometry, which allows bone and other organic matter trapped in the reamer, to more effectively be removed.